Abstract: P-type and n-type regions are defined in the first surface of a substrate upon which is formed an epitaxial layer of preferably Si—Ge material, preferably capped by Si material. During epitaxy formation, dopant in the defined regions diffuses down to form p-type and n-type junctions in the Si material, and diffuses up to form p-type and n-type junctions in the Si—Ge epitaxial material. Si junctions are buried beneath the surface and are surface recombination velocity effects are reduced. Photon energy striking the second substrate surface generates electron-hole pairs that experience the high bandgap of the Si materials and the low bandgap of the Si—Ge epitaxy. The tandem structure absorbs photon energy from about 0.6 eV to about 3.5 eV and exhibits high conversion efficiency.

Abstract: P-type and n-type regions are defined in the first surface of a substrate upon which is formed an epitaxial layer of preferably Si—Ge material, preferably capped by Si material. During epitaxy formation, dopant in the defined regions diffuses down to form p-type and n-type junctions in the Si material, and diffuses up to form p-type and n-type junctions in the Si—Ge epitaxial material. Si junctions are buried beneath the surface and are surface recombination velocity effects are reduced. Photon energy striking the second substrate surface generates electron-hole pairs that experience the high bandgap of the Si material and the low bandgap of the Si—Ge epitaxy.

Abstract: A power lateral PNP device is disclosed which includes an epitaxial layer; a first and second collector region embedded in the epitaxial layer; an emitter region between the first and second collector regions. Therefore slots are placed in each of the regions. Accordingly, in a first approach the standard process flow will be followed until reaching the point where contact openings and metal are to be processed. In this approach slots are etched that are preferably 5 to 6 um deep and 5 to 6 um wide. These slots are then oxidized and will be subsequently metalized. When used for making metal contacts to the buried layer or for ground the oxide is removed from the bottom of the slots by an anisotropic etch. Subsequently when these slots receive metal they will provide contacts to the buried layer where this is desired and to the substrate when a ground is desired. In a second approach the above-identified process is completed up through the slot process without processing the lateral PNPs.